This article originally appeared on VICE Spain.

On March 22, a Lithuanian man landed in Barcelona and boarded metro line 9 with his luggage, but without a ticket. Witnesses describe how he started behaving weirdly, and when security guards came up to him and asked for a ticket, he fell on the ground and started shaking and foaming at the mouth. The guards couldn’t have known, but that guy was a mule, a body packer: He had been carrying cocaine in his stomach in an attempt to smuggle it into Spain.

Transporting illegal drugs across borders is a business that can be as profitable as it can be lethal, and it has gained popularity in Spain since the economic crisis began. The man in question broke down because one of the bags of cocaine he carried in his stomach had ruptured. There wasn’t anything the emergency services could do—15 grams of coke ended his life. When forensic doctors investigated the body, they found 34 capsules of cocaine inside him.

Such cases are pretty rare—several doctors working in emergency units in Spanish hospitals told us that a patient who’s had a packet of drugs rupture inside him or her comes in about once a year. If everything goes according to plan, the bags leave the mule’s body in his or her stool. They’re in an ideal shape to be excavated and can stand the gastric acid that helps dissolve foods in your stomach.

Read the Remainder at Vice